Master Basic List Operations in Python — Without Using Built-in Methods in Python (Part 1)

In today’s post, we dive into performing basic list operations without using built-in Python methods.

Exercises like these help build strong problem-solving skills and deepen your understanding of Data Structures and Algorithms (DSA).

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Problem 1: Find the Minimum Value in a List

Problem

You are given a list of integers. Write a function find_min(nums) that returns the minimum number from the list without using Python’s built-in min() function.

If the list is empty, return None.

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Breakdown:

• First, we need a way to keep track of the minimum value. We initialize a variable to the first element:

  min_value = nums[0]

• Then, loop through the list. For each number, if it is smaller than our current min_value, we update min_value.
• If the list is empty, return None immediately.

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Full Solution:

def find_min(nums):
    if not nums:
        return None

    min_value = nums[0]

    for num in nums:
        if num < min_value:
            min_value = num
    return min_value

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Problem 2: Count Even and Odd Numbers

Problem

You are given a list of integers. Return a tuple (even_count, odd_count)

where even_count is the number of even integers, and odd_count is the number of odd integers.

Do not use any built-in Python methods like filter(), count(), etc.

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Breakdown:

• Initialize two counters:

  even_count = 0
  odd_count = 0

• Loop through each number:
  • If num % 2 == 0, it’s even → increment even_count.
  • Otherwise, it’s odd → increment odd_count.
• Finally, return a tuple (even_count, odd_count).

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Full Solution:

def count_even_odd(nums):
    even_count = 0
    odd_count = 0

    for num in nums:
        if num % 2 == 0:
            even_count += 1
        else:
            odd_count += 1

    return (even_count, odd_count)

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Final Thoughts

This marks the first part of practicing basic list operations without built-in functions.

Stay tuned and keep practicing — mastering these basics will give you a huge advantage in both coding interviews and real-world problem solving!

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